Bark-removing drum combined with hydraulic jet



Jan. 12, 1954 sc 2,665,721

BARK-REMOVING DRUM COMBINED WITH HYDRAULIC JET Filed Sept. 26, 1952 3 Sheets-Sheet 1 N if To U w 0 m N N N Q t0 g R I v F? H N w P H g) E \w 0 a o K) 2 a [Q Q N Tr \[Q N 0 N N INVENTOR.

AT TO RNEYS Jan. 12, 1954 T. N. BUSCH BARK-REMOVING DRUM COMBINED WITH HYDRAULIC JET 3 Sheets-Sheet 2 Filed Sept. 26, 1952 INVENTOR.

H a L m Wk m n w W% m w YXTTORNEYS Jan. 12, 1954 T. N. BuscH 2,665,721

' BARK-REMCVING DRUM COMBINED WITH HYDRAULIC JET Filed Sept. 26, 1952 3 Sheets-Sheet 3 FIGS.

IN VEN TOR.

Tw was Busch BY :ATTOPN EYS Patented Jan. 12, 1954 BARK-REMOVING DRUM COMBINED WITH HYDRAULIC JET Thomas N. Busch, Mobile, Ala. Application September 26, 1952, Serial No. 311,630

7 Claims.

This invention relates to an improvement in the method and apparatus of debarking logs, and more particularly to short lengths of logs, sticks, mine props, posts and similar forest products.

The invention is primarily predicated to the treatment of logs and sticks of the soft and hardwood species which may be used in the pulp industry after the bark has been removed. The logs or sticks must be treated to thoroughly remove all bark and any foreign matter collected on or which has become embedded in the logs. Great difificulty has been encountered in performing this operation mechanically and so far as is known there is no practical apparatus for accomplishing this result.

With the present invention the short logs and sticks will be rapidly cleaned of all bark and foreign matter, as the logs and sticks travel through a series of rotating drums wherein they are subjected to a tumbling action and thereby creating a rubbing of the logs and sticks together and against the fluted inner surface of the drums to cause a tearing and scuffing action which will break and remove the bark from the logs and sticks.

A further step in the treatment of the tumbling logs or sticks as they progress through the drums is to subject the logs or sticks to the action of hydraulic water jets between the adjacent drums to forcibly tear, rip or otherwise remove any undesired bark and foreign matter.

Another step and object is to have each drum section independently rotatable clockwise and counterclockwise, and so each drum section may rotate at a difierent speed from its adjacent drum section, or where all drum sections. may rotate.

at a uniform or like speed in a clockwise or counterclockwise direction.

The invention consists of certain novel features of construction and combinations of parts which will be more fully set forth and described herein and in the claims.

In the accompanying drawings:

Figure l is a longitudinal vertical sectional view of the invention, with some parts in elevation;

Figure 2 is a transverse vertical sectional view taken on line 2-2 of Figure 1;

Figure 3 is a view in elevation of the discharge end of the apparatus;

Figure 4 is a detail View in section taken on line 4-4 of Figure 2; and

Figure 5 is a detail view in elevation of one of the guide rollers for retaining the drum against lateral and longitudinal movement.

In the removal of the bark from the logs or sticks there are certain factors that must be considered in the operation of the apparatus, as various species of wood have different debarking characteristics. That is, consideration should be given to the time of year the tree is felled, and time elapsed from the felling of the tree, also, the species of the log or stick to be treated. With spring cut wood when the sap is beginning to run, the bark has a tendency to peel off readily, while with winter cut wood the bark is very tight and highly resistant to removal. Therefore, the speed and direction of rotation of the several drum sections would be determined by the operator, and would be dependent on the species of pulpwood being debarked, the season of the year and the degree of debarking efiiciency desired.

In the drawings a drum is disclosed composed of a plurality of independent drums or drum sections II, II which are preferably arranged in a horizontal plane, and each drum is suspended from a suitable framework l2. Each drum or drum section II is driven by a motor of the reversible type, reduction geared, and having a variable speed, so that each drum may be rotated clockwise or counterclockwise and at the desired speed.

The preferable size of these drums will be twelve feet by twelve feet, and the first or input drum ll would receive the load of logs or stroke and these logs or sticks would be discharged from the last drum. The unbarked logs or sticks would preferably be of short lengths from four feet to six feet and with a wide range of diameters, and particularly even where the sticks or logs are crooked. The drums are charged by a chute [4 until all of them contain the unbarked logs or sticks to a depth of one-fourth to onehaif their drum heights, this being governed somewhat by the character and contour of the sticks or logs being treated. The unbarked pulp wood would be contmuousiy introduced into the input end of the first drum at a greater cord wood volume per hour, which would also force or eject the wood at a greater rate per hour at the discharge end of the drum. The discharge end of the drum has an activated gate or dam l5 which can be operated to control the rate of discharge of the debarked pulp wood.

The frame l2 is preferably of metal construction, and consists of a plurality of posts or uprights l6 provided with longitudinal beams Ii, and a platform 18 across the top thereof. The drums II are each constructed of a plurality of spaced apart fluted metal slats 252 connected at their ends to annular rings 2!, and these rings 2| are provided with annular grooves or tracks 22 on their exterior surface for the reception of chains 23. The two chains 23 for each drum pass over sprocket wheels 24 mounted on shafts 25 journaled on standards 26 mounted on the platform it. As indicated in Figure 2, each endless chain 23 passes over two sprocket wheels 2:1, and the two chains 23 afford the support for each drum ll.

Mounted on the platform l8 are electric motors 28, one for each drum. These motors are of the reversible type, with reduction gearing and having variable speeds. Connected to each motor shaft 29 of the motors 23 is, a sprocket wheel 38. Each drum I! is provided intermediate its length and on its outer surface with an annular ring sprocket 32. An endless sprocket chain 3 passes over the ring sprocket 32 and sprocket wheel 39 to cause the drum to rotate clockwise or counterclockwise and at varying speeds. 1

The several drums ll, four being shown, although the number employed is optional, are arranged in end to end relation, and preferably in a horizontal plane. The ends of the adjoining drums are suitably spaced apart for the introduction of hydraulic jets 3b of a manifold 3'1, which is connected to a source of supply of water, not shown, by a pipe or conduit 38 provided with a valve 39. The manifold El and jets 36 are disposed beneath the drums, with the jets extending into the space between the-adjoining ends of adjacent drums, so that the water under pressure will be directed against the periphery of the logs supported by the bottoms of the drums.

Guide rollers 46, provided with flanges il at their ends are journaled on the beams if, and the flanges ll span the ring sprockets 32 of the drums to maintain the drums against lateral and longitudinal movement.

Mounted on the base 52 of the frame !2 is an endless belt conveyor 44 which receives the bark as it issues from the drums and between the slats 2i), .and extends lengthwise of the several drums.

Located above the base 12 and between the uprights iii are metal sheets 36 which converge from the uprights l6 downwardly beneath the conveyor M for collecting and draining the water issuing from. the jets. Enclosing the several drums within the frame 12 is metal sheathing l8 and 39. The sheathing is supported by the up-- rights Hi and platform It. and is spaced sufficiently away from the drums to allow the bark and any water ejected therefrom to be caught bythe sheathing and directed onto the endlessbelt 4%. The sheathing 19 converges toward the belt d4 so that any bark will be collected by the conveyor belt M.

The outlet gate I5 extends through slots 55) in the sheathing 49 and is mounted to slide in guides 52 supported by the frame 1.2, and is preferably operated by means of air cylinders 53 which are connected thereto by piston rods 5A. The gate i5 can be adjusted to the desired height to govern the discharge of the logs or sticks from the drum, naturally, the higher the gate is positioned the smaller the. quantity oi debarked logs and sticks that are discharged, and also, the logs. and sticks will be agitated and tumbled within the drums for a longer period. This adjustment or positioning of the gate will be governed bythe character of the pulpwood being debarked, as the bark on hard woods may require a longer period of agitation and tumbling in removing the bark.

In debarking spring out wood which contains considerable sap the bark has a tendency to peel off readily and under such conditions the several drums could all be rotated in the same direction and the speed of the drums adjusted to retain the pulpwood sticks a minimum of time in the drums. The speed of rotation of the drums could be gradually increased to such a speed that would not cause disintegration or injury to the pulp wood, that is, the speed should not be so great that the pulp wood would be caused to be plastered or thrown against the interior walls of V the drums due to centrifugal force. a

' Another illustration would be in debarking winter cut wood on which the bark is very tight and highly resistant to removal. In this instance the first drum could operate at say five revolutions per minute, and the second drum at six revolutions per minute, and the third at" seven revolutions per minute, and all rotatingclockwise. Under this condition or operation of the drums the difierence in the revolutions per minute would cause the scrubbing or rubbing action on the sticks partially contained in onev drum and partially in another drum. This principle is illustrated in Figure l of the drawings, and it will be noted that the logs or sticks in the process of slowly passing from the one drum to the adjoining drum, a twisting or rubbing action on the logs or sticks resting against the fluted rough inner surface of the drum will occur. This twisting action is more pronounced when the drums are rotated in opposite directions, that is, when the first and third drums are rotating counterclockwise and the second and fourth drums are rotating clockwise. Likewise this twisting action is to a much lesser degree when the several drums move at different speeds and all rotating for instance in a clockwise direction. The twisting action hastens the bark removal dueto the scrubbing and scufiing action that would take place between the logs and sticks as they are brought intocontact with one another and the fluted surface of the adjoining drums. It must be remembered that with these drums charged to say one-half their capacity there is bound to be the normal tumbling or churning action of the logs or sticks against one another due to the rotation of the drums.

It will be apparent that if the first and second drums were loaded with wood and rotating'in opposite directions, the first drum would hold the. sticksv as in a vise and the rotary motion of the two drums would rub or scrub the ends of the sticks projecting into it. The progress of the wood from. one drum to, another is not precipitous, but gradual, and consequently inexorablypressing towards the discharge end asmore wood is introduced into the. input end of the firstdrum.

Afurther step in the treatment of the logs or sticks as they are passing from one drum to another is in the provision of hydraulic jets 36 which are located between the adjoining ends of adjacent drums. These jets are located adjacent the bottoms of the drums so that the jets will be in close proximity tothe logs or sticks as they pass from one drum to the. other. The closer the jets to the logs the. greater debarking performed per gallon of water. The massed. weight of the wood in the. drums acts as an anvil andas a rigid support to the layer of wood underneath. The firmer the lower layer of wood is supported on the bottoms of the drums and inposition to be sub-- jected to the tremendous force of the hydraulic jets therebeneath the greater the erosion action that will be had on the logs in the removal of the bark therefrom. The pressure created by the mass of wood charged into the drums above the jets providesan opposing gravitational force to the jetting force beneath the logs. The pressure of the water supplied to the jets can be varied from one thousand to fourteen hundred lbs. to the sq. inch, the pressure selected being dependent on the tenacity of the bark to be removed. Naturally this pressure is dependent upon the character or the condition of the wood being treated, and this can be regulated to the treatment of soft and hard woods. As the unbarked wood passes by the jets the bark is literally ripped off in segments, the bark removal being further augmented by the abrasive, bruising action of the wood tumbling and twisting in the drum.

The pressure of water issuing from the jets would be governed by the character of pulp wood being treated and also whether the drums were all rotating in the same direction at the same speed or where each drum was rotating at a different speed. In instances of treating bark which is difficult to remove and where the sticks or logs are twisted and crooked, it is necessary to subject such wood to a harsher treatment, and therefore by causing these drums to rotate clockwise and counterclockwise with respect to each other and due to the capacity of the wood charged into these drums there will be a greater twisting, tumbling action among the logs as the drums are rotated, and also as these logs pass from one drum to another so that this twisting and twirling action hastens the removal of the bark and at the same time the logs are subjected to a further twisting action as they pass the stationary jets.

The gravitational force of the large mass of logs and sticks within the drum, and augmented by the tumbling and churning action of the logs and sticks, hold the periphery of the mass against the fluted surfaces of the drums where the sticks or logs are subjected to an abrasive action in removing the bark from the logs and sticks. It also subjects these logs or sticks on the peripheries of the mass to be exposed to the jets at a constant distance as the logs and sticks travel by the jets in the space intervening between the adjacent drums where the logs are subjected repeatedly and alternately to the erosive action. Further, the variable speeds and direction of rotation of the drums provides maximum abrasive action by the fluted inner surfaces of the drums against the unbarked surface of the wood as the logs or sticks gradually but steadily pass from one drum to another.

What I claim is:

1. An apparatus for debarking logs and sticks, comprising a series of drums, open at each end, arranged in end to end spaced relation, and each drum having a quantity of short logs and sticks therein which are of less length than the length of a drum, means for supporting said drums, means for rotating said drums to progressively feed the logs and sticks from one drum to another and causing said logs and sticks to have a tumbling and rubbing action within said drums, and means for injecting water under high pressure into the space between said adjoining drums and against the logs and sticks as they travel from one drum to another.

2. An apparatus for debarking logs and sticks, comprising a series of drums, open at each end, arranged in end to end spaced relation, means for delivering, less than capacity, a quantity of logs and sticks into each of said drums to provide a gravitational force and pressure upon the logs and sticks on the bottoms of said drums, means for supporting said drums, means for rotating said drums to progressively feed the logs and sticks from one drum to another and causing said logs and sticks to have a tumbling and rubbing action Within said drums, and means for injecting water under high pressure into the space between said adjoining drums and in engagement with the periphery of said logs and sticks traveling from one drum to another against the gravitational force and pressure of said logs and sticks.

- 3. An apparatus for debarking logs and sticks, comprising a series of drums, open at each end, arranged in end to end spaced relation, and each drum having a quantity of short logs and sticks therein which are of less length than the length of a drum, means for supporting said drums, means for rotating said drums to progressively feed the logs and sticks from one drum to another and causing said logs and sticks to have a tumbling and rubbing action within said drums, and means for injecting water under high pressure into the space between said adjoining drums and against the logs and sticks as they travel from one drum to another, and adjustable means at the discharge end of said last drum for governing the discharge of said logs and sticks from said drums.

4. An apparatus for debarking logs, comprising a series of open end drums arranged in end to end spaced relation, a chute for charging said drums with a quantity of short lengths of logs and sticks to be debarked, means for independently supporting each of said drums, means for independently rotating each of said drums to progressively feed the logs and sticks from one of said drums to another of the series and causing the logs and sticks to have a tumbling and scufifing action within the drum and with the inner walls of said drums, and hydraulic jets interposed in the space between the ends of said adjacent drums and positioned adjacent the bottom of said drums to subject the periphery of the logs and sticks to an erosive action of high pressure streams of water as they travel from one of said drums to another.

5. An apparatus for debarking logs, comprising a series of open end drums arranged in end to end spaced relation, means for charging said drums with a quantity of short lengths of logs or sticks to be debarked, means for independently supporting each of said drums for rotation, means for rotating and varying the speed of each of said drums in the progressive feeding of the logs and sticks from one of said drums to another and causing said logs and sticks to have a tumbling and scrubbing action with each other and against the inner walls of said drums, and means for introducing water under high pressure between the adjoining ends of said drums and against said logs and sticks as they travel from one drum to another.

6. The method of debarking a mass of barked logs and sticks as they progress through a plurality of drums rotating at different speeds, consisting in progressively feeding and rotating a mass of logs and sticks to create a tumbling and scuflfing action therebetween to remove the bark therefrom, and subjecting the logs and sticks on the bottom of the progressing mass and against the gravitational force of the mass of logs and sticks to the action of high pressure jets of water as the mass of logs and sticks passes from one rotating drum into an adjoining drumrotating at a speed different from that of said one drum. 7

'7. The method of debarking a mass of barked logs and sticks as they progress through a series of drums rotating at different speeds and wherein each alternate drum rotates in an opposite direction to that of an adjacent drum, consisting in progressively feeding and. rotating a mass of logs and sticks to create: a tumbling and'scuffing action between said logs and sticks to remove the bark therefrom, and subjecting the logs and stickson the bottom of the mass and against the gravitational force of the mass of logs and-sticks tothe action of high pressure jets of Water as the mass of logs and sticks passes from one rotating drum into an adjoining drum.

THOMAS BUSCI-I.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 5 7 1,984,872 Paulson Aug. 15, 1916 2,428,967 Gray Oct. 14, 1947 FOREIGN PATENTS 10 Number Country Date 52,015 Norway Jan. 16, 193 3 7 78,859 Sweden Nov. 7, 1933 OTHER REFERENCES Ser. No. 354,762, Holzkey et al. (A. P. C.), published May 11, 1943. 

